弟弟
younger brother
dìdi
What does 弟弟 mean?
弟弟 (dìdi) means 'younger brother' — the standard, everyday word for a male sibling who is younger than the speaker. Chinese kinship terms always specify age and side of the family, so unlike English 'brother,' 弟弟 cannot refer to an older brother (that's 哥哥, gēge). The reduplicated form 弟弟 is what family members and friends use; the single 弟 (dì) appears in formal writing or compounds (兄弟, xiōngdì, 'brothers').
The second 弟 in 弟弟 is toneless in normal speech, giving the typical neutral-tone pattern of family terms (爸爸, 妈妈, 姐姐). 弟弟 can also be used affectionately by adults to address a young boy they don't know — like English 'little guy' — though this usage is mostly limited to small children.
Character breakdown
younger brother
younger brother (reduplicated, neutral tone)
Measure word for 弟弟
Example sentences
我有一个弟弟。
Wǒ yǒu yí ge dìdi.
I have a younger brother.
neutral
我弟弟今年八岁。
Wǒ dìdi jīnnián bā suì.
My younger brother is eight this year.
spoken
他的弟弟很可爱。
Tā de dìdi hěn kě'ài.
His younger brother is so cute.
spoken
弟弟在学校学习。
Dìdi zài xuéxiào xuéxí.
My younger brother is studying at school.
neutral
我和弟弟一起去公园。
Wǒ hé dìdi yìqǐ qù gōngyuán.
My younger brother and I are going to the park together.
neutral
Common phrases with 弟弟
Synonyms
兄弟 means 'brothers' as a category (older + younger together) or 'bro / buddy' between male friends. 弟弟 specifically means YOUR younger brother.
Single-character 弟 is the formal/written form, used in compounds (表弟 'younger male cousin', 师弟 'junior schoolmate'). In everyday speech you double it: 弟弟.
Don't confuse 弟弟 with
妹妹 is 'younger sister.' Same age relationship to the speaker, different gender. The pair is 弟弟 / 妹妹.
哥哥 is 'older brother.' Chinese always splits siblings by age, so you cannot use 弟弟 for an older brother.
第 is a prefix for ordinal numbers (第一 'first', 第二 'second'). Same pinyin as 弟, completely unrelated meaning. Different character.
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